Linear drive

ABSTRACT

A linear drive comprising a housing having a tube body ( 3 ) and a terminally mounted housing cover ( 4 ). In the wall of the tube body ( 3 ) a cavity is located, into which a sensor ( 14 ) extends. The rear end section ( 21 ) of the sensor ( 14 ) is in a socket ( 18 ), arranged as an extension of the cavity, of the housing cover ( 4 ). This socket ( 18 ) is formed by a recess ( 22 ) and its opening ( 26 ) extends from the end face ( 23 ) facing the tube body ( 3 ), of the housing cover ( 4 ) as far as the adjacent lateral outer face ( 24 ) of the housing cover ( 4 ). The electrical lead means for the sensor ( 14 ) are associated with the lateral section of the recess&#39;s opening ( 26 ).

FIELD OF THE INVENTION

The invention relates to a linear drive comprising a housing having atube body containing a receiving space for a linearly moving drive partand a housing cover mounted on an end side of the tube body, aperipherally closed cavity formed in the wall of the tube body, whichcavity is open toward the tube body's end face facing the housing cover,and at least one socket, which is provided as an axial extension of thecavity on the housing cover and also provided for the rear end sectionof a sensor serving for detection of at least one position of the drivepart, said sensor extending from the socket into the cavity in the tubebody.

BACKGROUND OF THE INVENTION

A linear drive of this type is described in the German patentpublication 4,306,539 C2. In this known case the tube body possesses achannel-like cavity, formed the wall thereof and aligned with a socket,in the form of a receiving hole, in the housing cover mounted at theend. The sensor is designed in the form of rod and is plugged from therear side of the housing cover through the receiving hole into thecavity in the tube body, the rear end section of the sensor being fixedin the receiving hole. At the rear end section of the sensor electricalleads are provided and associated with the rear side (opposite to thetube body) of the housing cover whence same make possible electricalcontact and connection with the sensor.

In the case of linear drive the measure necessary for the holding inplace of the sensor on the housing cover take up a relatively largespace in the longitudinal direction of the linear drive. Sameaccordingly has a relatively large overall length. Therefore it is oneobject of the present invention to create a linear drive, which whileproviding for secure holding of the sensor in place has a small overalllength.

SUMMARY OF THE INVENTION

In order to achieve this object there is a provision such that thesocket is constituted by a recess in the housing cover, the opening ofsuch recess extending from the end face, facing the tube body, of thehousing cover continuously as far as the adjacent lateral outer face ofthe housing cover, the electrical lead means of the sensor beingassociated with the lateral section of the recess's opening.

It is in this manner that the rear end section of the sensor is seatedin a recess, extending along a corner of the housing cover, theelectrical contact with the sensor being possible from the side of thehousing cover. The length, as measured in the longitudinal direction ofthe linear drive of the recess may be made relative short, somethingwhich means short dimensions of the housing cover and provides spacewithin the housing cover for other means, which are necessary for theoperation of the linear drive. Since the electrical lead means of thesensor are associated with the lateral section of the recess's opening,satisfactory accessibility is provided for. Finally it is also possibleto ensure unloseable fixation of the sensor in place, sincedeinstillation is only possible by removal of the housing cover, thispreventing unauthorized access.

Further advantageous developments of the invention are defined in thedependent claims.

It is preferred for the rear end section of the sensor to be in the formof an attachment section, by way of which the sensor is so held in therecess, that, as considered in the state with the tube body removed, itextends firmly held in a transverse position, that is to say it issecured in the transverse direction and practically incapable ofmovement, extending away from the housing cover. Therefore when mountingthe sensor in place it is possible to firstly secure same with theattachment section in the recess in the housing cover in order in thecourse of later fixing of the housing cover on the tube body tosimultaneously insert outwardly extending longitudinal section of thesensor into the cavity.

It is particularly advantageous for the rear end section of the sensorto be designed in the form of an attachment section, which renderspossible plugged mounting of the sensor in the recess. In this case adesign of the plug connecting means is preferred such that the directionof plugging coincides with the longitudinal direction of the lineardrive.

The plug connecting means may for example be constituted by wells, whichextend in the direction of plugging on the housing cover, such recessesbeing provided in the lateral faces of the recess and by lateralprojections, fitting in the wells, of the sensor. Furthermore a reversedassociation of the plug connecting means would be possible here.

A design is preferred such that the sensor has its one attachmentsection held immovably in the axial direction between the housing coverand the tube body. It is in this manner that an exact, axially securedpositioning of the sensor in relation to the housing of the linear driveis ensured without additional attachment means. This is for instancemade possible by having the attachment section and the recess so matchedin their dimensions that the sensor is proud of the tube body to a smallextent when housing cover is not mounted on the tube body so that in themounted state of the housing cover the tube body is acted upon by thefacing end side of the tube body.

It is convenient for the recess to be closed, apart from the openingthereof extending from the end face as far as the lateral external face.

Preferably no fixation of the sensor's longitudinal section, extendinginto the cavity in the tube body, is required so that consequently thesensor is conveniently free right from the housing cover along its fulllength where it projects into the cavity of the tube body and apart fromits rear end section is not fixed anywhere. At this point it is to benoted as well that the axial overall length of the sensor's longitudinalsection extending into the cavity is preferably selected to be less thanthe overall length of the tube body, it being sufficient for the sensorto extend so far into the cavity that the part is covered or the pointis reached, which is to be detected.

Preferably the cavity extends along the full overall length of the tubebody and opens at the opposite end faces of the tube body. If housingcovers are provided on both ends of the tube body and such housingcovers have a recess with an associated sensor, it is accordinglypossible for both sensors to extend from opposite sides into one and thesame cavity.

Since the sensor may readily be so designed that the section of itslength extending into the cavity does not require any transversesupporting action, the cross sectional shape of the cavity does not haveto meet any special requirements and practically any design is possible.This means that the cross sectional shape of the cavity may be adaptedto comply with other features of the tube body. It is for instancepossible to have a tube body in the form of a extrude, which in its wallhas a plurality of axially continuous channels distributed about theperiphery of the receiving space, such channels being provide to saveweight and material, one of such channels being utilized as a cavity toreceive the sensor.

It is preferred for the electrical lead means of the sensor to bedesigned in the form of plug means so that a cable may be replaced asdesired. Furthermore the sensor preferably has an essentially L-likeshape, the longer limb extending into the cavity of the tube body whilethe shorter limb is provided on the rear end section and extends throughthe laterally aligned section of the recess's opening to the outside. Inthis case the electrical lead means are preferably provided on theshorter L limb of the sensor.

The sensor may be provided with light producing display means on therear end section, such display means making it possible to indicate theoperational state of the sensor. In this connection in the case of aparticularly economic structure there may be such a provision that thesensor has a housing which is transparent at least at the rear endsection, through which housing the light signals from the light displaymeans are visible from the outside. Accordingly the light producingdisplay means may be readily seen while the display area protected in anoptimum manner.

The design in accordance with the invention is more particularlyadvantageous in the case of linear drives operated using fluid power.However, the invention is also applicable to linear drivess, which areoperated with other types of energy, as for example electric power.

In the following the invention will be described with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first design of the linear drive in accordance with theinvention in perspective.

FIG. 2 shows a section of the linear drive of FIG. 1, which is limitedto the representation of the part of the tube body and of the tube bodyand a rear housing cover, the components being illustrated in anexploded view.

FIG. 3 shows housing cover of the linear drive in accordance with FIGS.1 and 2 in a separate view with the sensor secured thereto.

FIG. 4 shows an end-on view of the arrangement of FIG. 3 looking in thedirection of the arrow IV.

FIG. 5 is an end-on view of the arrangement of FIG. 2 looking in thedirection of the arrow V.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The drawings show a fluid power operated linear drive 1, which possessesan elongated housing 2, a tube body and housing covers 4 mounted of thetwo ends of the tube body 3 permanently.

In the interior of the housing 2 a preferably cylindrical receivingspace 5 is provided, which extends in the longitudinal direction of thehousing 2 and which is delimited at the external periphery by the wall 6of the tube body and at the end by the two housing covers 4.

A drive part 7 is provided in the receiving space 5 and this drive part7 is in the form of a piston in the case of a fluid power version of thelinear drive and is able to move inthe receiving space 5 in thedirection of the longitudinal axis 8 of the housing. The drive part 7divides the receiving space 5 axially into two working chambers intowhich a respective fluid duct 12 (running in the adjacent housing cover4) opens and by way of such fluid duct the associated power duct may besupplied with fluid power medium, as for example compressed air, or maybe depressurized or, respectively, vented. This means that the drivepart 7 may be caused to perform a linear movement in the directiondefined by the longitudinal axis 8 of the housing, and such motion maybe transmitted to a transmitting part 13 or dog outside the housingengaged with the drive part 7.

Said transmitting part 13 is, in the present working example, in theform of a piston rod extending through the front housing cover 4, itmaking sliding engagement with such front housing cover so thataccordingly the corresponding housing cover 4 may be termed a bearingcover. The opposite, rear housing cover 4 is in the form of a plainterminal cover.

In the case of an alternative design (not illustrated), the linear driveis in the form of a rod-less linear drive so that both housing covers 4act as terminal housing covers and the transmission of power between thedrive part 7 and the transmitting part 13 takes place in some othermanner, for example by magnetic force or by means of a dog extendingthrough a longitudinal slot in the housing 2.

In the case of a further design, not illustrated, of the linear drive asan electrical drive the drive part 7 is operated by electrical energy,for instance using a lead screw drive.

The linear drive 1 is provided with a position detecting means, whichrenders it possible to detect a plurality of positions assumed by thedrive part 7 in relation to the housing 2. In the case of such positionsto be detected it is for example a question of terminal positions of thedrive part 7 as defined by the maximum stroke of the drive part 7. Thissystem includes a respective sensor 14 for the two axial end parts ofthe housing 2, such sensor being able to respond, without makingphysical contact, to an actuating element constituted by the drive part7 or provided therein, when such actuating element, in the course of itslinear motion, assumes a position near suitable detection means 15 forthe sensor 14 and more especially assumes such a position that it isradially opposite the detection means 15 on the inside thereof.

The actuating element may for instance be in the form of a permanentmagnet and the sensor 14 may be a so-called reed switch, in the case ofwhich the detection means 15 are operated by the magnetic field of theactuating element.

The arrangement and design of the two sensors 14 is identical in thepresent working example so that the following detailed account is onlyin relation to the sensor 14 which is associated with the rear housingcover 4. The description therefore applies also for the sensor providedon the front housing cover 4, it being necessary to mention that thelinear drive 1 may be designed so that a sensor is provided only on onehousing cover and each housing cover may be provided with severalsensors.

The respective sensor 14 is provided with a cavity 16 in the wall 6,which peripherally delimits the receiving space 5, of the tube body 3,such cavity 16 preferably extending in the longitudinal direction of thetube body and being entirely enclosed in the peripheral direction. Suchcavity 16 opens at the end face, herein termed the first end face 17, ofthe tube body, on which the housing cover 4 is mounted. With a view tosimplifying manufacture the cavity 16 extends along the full overalllength of the tube body 3 and opens at its opposite end faces. Thismeans that it is possible to have a tube body 3 in the form of anextrude in whose wall 6 one or more axially continuous channels 19extend which are distributed about the periphery of the receiving space5 and of which one is utilized as a cavity 16.

As an axial extension of the cavity 6 a socket 18 is provided for therear end section 21 of the sensor 14. This socket 18 is constituted by arecess 22 in the housing cover 4, which is placed like a cutting in thetransitional area between the end face (in the following termed thesecond end face 23) of the housing cover 4 and the lateral outer face 24in the housing cover 4, such face 24 facing radially outward in relationto the housing's longitudinal axis 8. Since the second end face 23merges with the lateral outer face 24 at a surrounding edge 25, whichdependent of the design may be sharp or blunt, it is possible to saythat the recess 22 severs the edge 25 and in effect constitutes a recessextending along a corner. The recess's opening 26, which defines thetransition to the second end face 23 and the lateral outer face 24 thusthe tube extends from the second end face 23, which is turned toward thebody 3, continuously as far as the adjacent lateral outer face 24, ithaving a first opening section 27 opening at the second end face 23 anda second opening section 28 opening at the lateral outer face 24. Theseopening sections 27 and 28 merge with each other continuously, i. e.without interruption.

The sensor 14 is an elongated component and in the working examplepossesses an essentially L-like shape. The transitional zone between thelonger limb 32 and the short limb 33 here defines the rear end section21 of the sensor 14. In the working embodiment illustrated the same isin the form of an attachment section 34, by way of which the sensor 14is fixed in the recess, it having its longer limb 32 projecting out ofthe first opening section 27 having its shorter limb 33 extending out ofthe second opening section 28 of the recess 24. The longer limb 32 hereextends in parallelism to the housing's longitudinal axis 8 and extendsinto the associated cavity 16, whose opening, provided at the first endface 17, is aligned with the first opening section 27, provided at thesecond end face 23 of the housing cover 4, of the recess 22.

The above mentioned detection means 15 are located in the longer limb32, with which same are preferably integrated. They are internallyconnected with electrical lead means 35 for the sensor, which serve formaking an electrical contact and are arranged in the lateral, secondsection 28 of the recess's opening 26. In the working embodiment theelectrical lead means 35 are provided on the shorter limb 33 and arepreferably in the form of plug means, which render possible a detachableconnection with electrical leads for the connection of other equipment,for instance in the form of a cable. It would be feasible to haveelectrical leads in the form of fixed conductors or electrical leadmeans in the form of wireless signal transmitting means or as forinstance infrared transmission means or using radio waves.

In the mounted state the sensor 14 is consequently seated so that itsrear end section 21 fits into the recess 22, whence it extend into theassociated cavity 16 in the tube body 3 and whence the electricalcontact making means extends outward to the side. Removal of the sensor14 is only possible after firstly removing the housing cover 4,something which prevents tampering. Furthermore, the locking of theattachment section 34 in the recess 32 ensures a permanent exact settingof the axial position of the sensor 14 and accordingly the detectionmeans 15 provided on same. Without complex adjustment it is thuspossible to set the position of the sensor 14 as part of assembly workby the manufacturer of the linear drive. Here there is the possibilityof making available several sensors 14 which are different as regardstheir axial overall length and, respectively, the axial position of thedetection means 15 so that customization may include the mounting of asensor, which exactly corresponds to the relevant position of the drivepart 7. In this respect it would also be possible to so design thedetection means 15 that same are suitable for detecting a plurality ofpositions.

Preferably the attachment section 34 of the sensor 14 is so adapted tothe configuration of the recess 22 that when same is mounted in therecess 22 it is held in the recess 22 even when housing cover 4 is notyet installed on the tube body 3. This opens up the possibility ofprefixing the sensor 14 on the housing cover 4 and during followingfitting of the housing cover 4 automatically positioning the sensor 14in place.

FIG. 3 shows the housing cover 4 removed from the tube body 3 and withthe sensor 14 fitted in the recess 22, the sensor 14 being so held inthe recess 22 that it is firmly held in the transverse position, that isto say practically immovably held in the transverse position, and itextends away from the housing cover 4.

The consequence of this is that with the housing cover 4 mounted on thetube body 3, the sensor 14 has its entire length in the tube body sothat it is practically free on all the sides in the cavity 16 and apartfrom the attachment section 34 is not fixed to the housing anywhere.This means that adaptation of the cross sectional shape of the cavity 16to that of the length section, projecting in the cavity 16, of thesensor 14 is unnecessary. The sole condition as regards the shape of thecavity 16 is that same should render possible insertion of the sensor14. It is in this manner that it is generally possible to use readilyavailable extruded tubular material for the tube body 3, the crosssectional shape of the longer limb of the sensor 14 being so designedthat insertion into the channels 19 in the wall 6 of the tube body 3 maybe undertaken without any trouble.

It is convenient for the attachment section 34 of the sensor 14 to be sodesigned that it is able to be fixed in position by plugging in therecess 22. The arrangement is then preferably such that the direction 36of plugging indicated by the double arrow in FIG. 3 is at a right angleto the second end face 23 of the housing cover 4.

The plug means 37 rendering possible the plug connection are preferablyso designed that they only allow one degree of freedom for the sensor 14in the direction 36 of plugging, whereas all other degrees of freedomare locked. This means that more particularly it is impossible for theplugged in attachment section 34 to be removed past the second section28 of the recess 22 or to be turned about its longitudinal axis. Such asecure fixation in place furthermore ensures an exact position withcorrespondingly exact detection.

In the working embodiment the plug connection means 37 are constitutedby groove-like wells 38 running in the plugging direction 36 on sides ofthe recess 22, such wells being located on the two mutually oppositeside faces 42 of the recess 22. These side faces 42 lie in planes, whichrun at a right angle to the second end face 23 and at the same timeextend athwart the lateral outer face 24. The wells 38 open at thesecond end face 23 and extend approximately along the length, asmeasured in the plugging direction 36, of the recess 22.

The plugging means 37 provided on the attached section 34 are formed bylaterally projecting and for example rib-like projections 43, which alsorun in the plugging direction 36 and which on insertion of the sensor 14fit into the wells 38. It will be clear that the arrangement may also bereversed so that the projections are located on the lateral wall of therecess 22 and the wells 38 are in the lateral face of the attachmentsection 34.

The depth of insertion, as measured in the plugging direction 36, of theattachment section 34 may be preset by having a matching length of theplugging connection means 37. Preferably, however the limitation of thedepth of insertion is by the rear delimiting face 44, of the recess 22opposite the first opening section 27 in the plugging direction 36,against which face 44 the inserted sensor rests on the rear face 45 ofthe attachment section 34. Here it is an advantage for the reardelimiting face 44 of the recess 22 to have a concave shape asillustrated and for the rear side 45 of the attachment section 34 to beconvex and complementary thereto.

The sensor 14 can be secured in the desired position without usingspecially adapted attachment means, that is to say simply by thecooperation with the housing cover 4 and the tube body 3. For thispurpose the shape and the overall length of the attachment section 34and of the recess 22 may be so matched that in the position insertedinto the recess 22 but before mounting the housing cover 4 on the tubebody the attachment section 34 slightly projects past the zones of thesecond end face 23 adjacent to the recess 22. The correspondinglyprojecting part of the attachment section 34 is depicted in FIG. 3 at46. If now the housing cover 4 is mounted on the tube body 3 and isclamped to same, for example using attachment screws 47 or otherattachment means, axially, the projecting part 46 will be acted upon bythe first end face 17 of the tube body 3. As a result the sensor 14 willhave its attachment section 34 clamped in an axially immovable fashionbetween the housing cover 4 and the tube body 3.

In the case of this type of attachment manufacture of the attachmentsection 34 of a material is preferred which possesses a certain degreeof deformability, for instance a plastic material. Furthermore, theamount by which the part 46 stands proud is selected to be relativelysmall. This means that the desired clamping effect is produced andsimultaneously a flush surface-to-surface contact of the two end faces17 and 23 is ensured.

The recess 22 is preferably closed on all sides apart from the recess'sopening 26 so that more particularly entry of foreign matter isprevented.

In order to indicate particular operational states of the sensor 14 thesensor 14 is provided with light producing display means 48 at its rearend section 21, such means being for example one or more LEDs. Such LEDsare located in the interior of the sensor 14 and may be arranged on aprinted circuit board, not illustrated in detail, which carries thedetection means 15 and/or the other electronic components required forthe operation of the sensor 14. In order nevertheless to ensure goodvisibility of the LED signals, the housing 52 of the sensor 14 ismanufactured of a transparent material at least adjacent to theattachment section 34 and preferably entirely. It is in this manner thatit is possible for all functional parts of the sensor to be encapsulatedin a fluid-tight fashion without reducing the indicating effect thereof.

In the working embodiment the sensors 14 provided on the two housingcovers 4 extend into different cavities 16 in the housing 2. It willhowever be clear that a common cavity could be provided for all sensors14, if this should be allowed by the overall length of the sensorsection extending into the cavity.

Even in the case of a relatively short length of the recess 22, asmeasured in the direction of the housing's longitudinal axis 8, anextremely reliable fixation of the sensor 14 may be ensured. Theconsequence of this is that the housing cover 4 has an extremely shortoverall length, this leading to compact dimensions of the linear drive1. Moreover, the attachment means for the sensor 14 only occupy anextremely small fraction of the overall volume of the housing cover 4 sothat there is sufficient free space for the installation or integrationof further functional components in the housing cover 4. FIG. 1 showsfor example a set screw 53 arranged in an axial continuation of therecess 22 in the housing 4, for a speed regulating valve or for apneumatic damping means to slow down when approaching the terminalposition.

What is claimed is:
 1. A linear drive comprising a housing having a tubebody containing a receiving space for a linearly moving drive part and ahousing cover mounted on an end side of the tube body, a peripherallyclosed cavity formed in a wall of the tube body, which cavity is opentoward the tube body's end face facing the housing cover, and at leastone socket, which is provided as an axial extension of the cavity intothe housing cover and also provided for a rear end section of a sensorserving for detection of at least one position of the drive part, saidsensor extending from the socket into the cavity in the tube body,wherein the socket is constituted by a recess in the housing cover, anopening of such recess extending from the end face, facing the tubebody, of the housing cover continuously as far as an adjacent lateralouter face of the housing cover an electrical lead means of the sensorbeing associated with a lateral section of the recess's opening.
 2. Thelinear drive as set forth in claim 1, wherein a rear delimiting face,which is opposite to a section of the recess's opening turned toward thetube body, is concave in shape, the rear end section of the sensorhaving a convex shape which is complementary of an associated rear side.3. The linear drive as set forth in claim 1, wherein apart from therecess's opening, the recess is closed.
 4. The linear drive as set forthin claim 1, wherein starting at the housing cover, the sensor has itsfull length, which extends into the cavity, free on all sides and apartfrom its rear end section is not fixed at any point.
 5. The linear driveas set forth in claim 1, wherein the tube body is in the form of anextrude and in its wall has a plurality of axially continuous channels,distributed about the periphery of the receiving space, one such channelforming the cavity.
 6. The linear drive as set forth in claim 1, whereinthe electrical lead means of the sensor are in the form of plug means.7. The linear drive as set forth in claim 1, wherein the sensor haslight producing display means, same being placed at the rear endsection.
 8. The linear drive as set forth in claim 7, wherein the sensorpossesses a housing which is transparent at least at the rear endsection, through which the light signal of the light producing displaymeans, enclosed by the housing, may be seen from the outside.
 9. Alinear drive comprising a housing having a tube body containing areceiving space for a linearly moving drive part and a housing covermounted on an end side of the tube body, a peripherally closed cavityformed in a wall of the tube body, which cavity is open toward the tubebody's end face facing the housing cover, and at least one socket, whichis provided as an axial extension of the cavity into the housing coverand also provided for a rear end section of a sensor serving fordetection of at least one position of the drive part, said sensorextending from the socket into the cavity in the tube body, wherein thesocket is constituted by a recess in the housing cover, an opening ofsuch recess extending from the end face, facing the tube body, of thehousing cover continuously as far as an adjacent lateral outer face ofthe housing cover an electrical lead means of the sensor beingassociated with a lateral section of the recess's opening and whereinthe rear end section of the sensor is designed in the form of anattachment section by way of which the sensor is so held in the recessthat as viewed after removal of the tube body, same extends in a firmlyheld transverse position from the housing cover.
 10. The linear drive asset forth in claim 9, wherein the plug connecting means on the housingcover are constituted by wells extending in a direction of plugging inlateral faces of the recess and on the sensor are constituted by lateralprojections fitting into the well or vice versa.
 11. A linear drivecomprising a housing having a tube body containing a receiving space fora linearly moving drive part and a housing cover mounted on an end sideof the tube body, a peripherally closed cavity formed in a wall of thetube body, which cavity is open toward the tube body's end face facingthe housing cover, and at least one socket, which is provided as anaxial extension of the cavity into the housing cover and also providedfor a rear end section of a sensor serving for detection of at least oneposition of the drive part, said sensor extending from the socket intothe cavity in the tube body, wherein the socket is constituted by arecess in the housing cover, an opening of such recess extending fromthe end face, facing the tube body, of the housing cover continuously asfar as an adjacent lateral outer face of the housing cover an electricallead means of the sensor being associated with a lateral section of therecess's opening and wherein the rear section of the sensor is designedin the form of an attachment means by way of which the sensor may beheld in position in the course of assembly by plugging.
 12. The lineardrive as set forth in claim 11, wherein the attachment section and therecess are so provided with cooperating plug connecting means that thesensor may be plugged in past the section, facing the tube body, of therecess's opening into the recess and in the plugged-in state, is heldimmovably in the position athwart a direction of plugging.
 13. Thelinear drive as set forth in claim 11, wherein the sensor is clamped atits attachment section in an axially immovable fashion between thehousing cover and the tube body.
 14. The linear drive as set forth inclaim 13, wherein, when the housing cover is not mounted on the tube,the attachment section of the sensor extends a small distance past theend face facing the tube body of the housing cover and in the mountedstate of the housing cover is acted upon by the facing end face of thetube body.
 15. A linear drive comprising a housing having a tube bodycontaining a receiving space for a linearly moving drive part and ahousing cover mounted on an end side of the tube body, a peripherallyclosed cavity formed in a wall of the tube body, which cavity is opentoward the tube body's end face facing the housing cover, and at leastone socket, which is provided as an axial extension of the cavity intothe housing cover and also provided for a rear end section of a sensorserving for detection of at least one position of the drive part, saidsensor extending from the socket into the cavity in the tube body,wherein the socket is constituted by a recess in the housing cover, anopening of such recess extending from the end face, facing the tubebody, of the housing cover continuously as far as an adjacent lateralouter face of the housing cover an electrical lead means of the sensorbeing associated with a lateral section of the recess's opening andwherein the cavity extends along the entire overall length of the tubebody and opens at opposite end faces of the tube body.
 16. A lineardrive comprising a housing having a tube body containing a receivingspace for a linearly moving drive part and a housing cover mounted on anend side of the tube body, a peripherally closed cavity formed in a wallof the tube body, which cavity is open toward the tube body's end facefacing the housing cover, and at least one socket, which is provided asan axial extension of the cavity into the housing cover and alsoprovided for a rear end section of a sensor serving for detection of atleast one position of the drive part, said sensor extending from thesocket into the cavity in the tube body, wherein the socket isconstituted by a recess in the housing cover, an opening of such recessextending from the end face, facing the tube body, of the housing covercontinuously as far as an adjacent lateral outer face of the housingcover an electrical lead means of the sensor being associated with alateral section of the recess's opening and wherein the sensor has anessentially L-like configuration, a longer limb extending into thecavity and a shorter limb being provided on the rear end section andextending through the laterally aligned section of the recess's opening.17. The linear drive as set forth in claim 16, wherein the electricallead means are provided on the shorter limb of the sensor.
 18. A lineardrive comprising a housing having a tube body containing a receivingspace for a linearly moving drive part and a housing cover mounted on anend side of the tube body, a peripherally closed cavity formed in a wallof the tube body, which cavity is open toward the tube body's end facefacing the housing cover, and at least one socket, which is provided asan axial extension of the cavity into the housing cover and alsoprovided for a rear end section of a sensor serving for detection of atleast one position of the drive part, said sensor extending from thesocket into the cavity in the tube body, wherein the socket isconstituted by a recess in the housing cover, an opening of such recessextending from the end face, facing the tube body, of the housing covercontinuously as far as an adjacent lateral outer face of the housingcover an electrical lead means of the sensor being associated with alateral section of the recess's opening and wherein the drive part is inthe form of an axially sliding piston.
 19. A linear drive comprising ahousing having a tube body containing a receiving space for a linearlymoving drive part and a housing cover mounted on each opposite end sideof the tube body, a peripherally closed cavity formed in a wall of thetube body, which cavity is open toward the tube body's end face facingthe housing cover, and at least one socket, which is provided as anaxial extension of the cavity into the housing cover and also providedfor a rear end section of a sensor serving for detection of at least oneposition of the drive part, said sensor extending from the socket intothe cavity in the tube body, wherein the socket is constituted by arecess in the housing cover, an opening of such recess extending fromthe end face, facing the tube body, of the housing cover continuously asfar as an adjacent lateral outer face of the housing cover an electricallead means of the sensor being associated with a lateral section of therecess's opening and wherein, at least one such housing cover has atleast one recess for a the sensor.